title: Has the prevalence and severity of symptoms of asthma changed among children in New Zealand? ISAAC Phase Three.
abstract: OBJECTIVE
  To investigate time trends in prevalence of symptoms of asthma by repeating, during 2001-3 (Phase Three), the International Study of Asthma and Allergies in Childhood (ISAAC) Phase One study that was conducted in New Zealand in 1992-3.
  
  
  METHODS
  ISAAC Phase Three involved repeating the cross-sectional questionnaire survey of two age groups of school children (6-7 years and 13-14 years, children and adolescents respectively) using the same methodology as Phase One. In New Zealand it was conducted in Auckland, Bay of Plenty, Christchurch, Nelson, and Wellington.
  
  
  RESULTS
  After 9 years, reported asthma ever increased from 24.6% to 30.2% in children and from 24.1% to 32.4% in adolescents (p<0.001). Current wheeze (written questionnaire) significantly decreased in children from 23.6% to 22.2% (p=0.002) and in adolescents from 29.7% to 26.7% (p=0.047), and for the video questionnaire from 18.1% to 11.1% (p<0.001). There was a significant reduction in wheezing limiting speech from 5.0% to 3.7% in children, and 7.9% to 6.2% in adolescents. Little regional variation was found. A higher proportion of children with asthma symptoms now report having ever had asthma.
  
  
  CONCLUSIONS
  The decrease in prevalence and severity of symptoms of asthma is encouraging, but the reasons for these trends are currently unclear. Increases in asthma labelling are likely to be due to greater awareness of asthma. A trend of decreasing prevalence of asthma symptoms, if maintained, has positive implications for lessened burden of disease among asthmatics and lowered cost of treatment.
authors.affiliation: Department of Paediatrics: Child and Youth Health, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland Mail Centre, Auckland 1142, New Zealand. mi.asher@auckland.ac.nz
authors.forename: M Innes
authors.initials: MI
authors.lastname: Asher
authors.forename: Alistair W
authors.initials: AW
authors.lastname: Stewart
authors.forename: Tadd
authors.initials: T
authors.lastname: Clayton
authors.forename: Julian
authors.initials: J
authors.lastname: Crane
authors.forename: Philippa Innes
authors.initials: PI
authors.lastname: Ellwood
authors.forename: Richard
authors.initials: R
authors.lastname: Mackay
authors.forename: Ed
authors.initials: E
authors.lastname: Mitchell
authors.forename: Chris
authors.initials: C
authors.lastname: Moyes
authors.forename: Philip K
authors.initials: PK
authors.lastname: Pattemore
authors.forename: Neil
authors.initials: N
authors.lastname: Pearce
mesh_terms: D000293:Adolescent; D000367:Age Factors; D001249:Asthma / Q000453:epidemiology*; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D009520:New Zealand / Q000453:epidemiology; D015995:Prevalence; D012135:Respiratory Sounds; D012720:Severity of Illness Index; D012737:Sex Factors; D011795:Surveys and Questionnaires